Manufacture of building blocks



April 1941., J STRAUB 2,2316% MANUFACTURE OF BUILDING BLOCKS Filed Jan.11, 1939 2 Sheets-Sheet l April 8, 1941. F i RA -B 2,237,691

MANUFACTURE OF BUILDING BLOCKS Filed Jan. 11, 1939 2 Sheets-Sheet 2 19TTDRJVEK Patented Apr. 8, 1941 UNITED STATESPATENT OFFICEiffiiiiffuitffilifilfff Application January 11, 1939, Serial No. 250,370

' 8 Claims. (01. 25-41) My invention is an improvement in themanufacture of concrete building blocks and the like, and in the methodand apparatus involved in such manufacture.

In the making of such blocks of a suitable aggregate such as sand andgravel, cinders, etc. mixed with cement and Water and subjected toressing or tamping operations, it is desirable in some cases to secure asmooth or approximately smooth outer surface. In my prior Patents No.1,651,420, 1,682,359, 1,692,355, 1,987,721 and 2,099,946 are discloseddifferent means and various methods of accomplishing such results whichhave proven generally satisfactory.

In the development of concrete building units of the kind involved, itis becoming increasingly desirable to surface the blocks by trowellingaction against the plastic face or faces, and the present invention hasin view to improve and refine such treatment, in the manner hereinafterdescribed.

As is generally understood in the art, and as fairly disclosed in mypreceding patents, the trowelling operation tends to not only smooth thesurface, but to regulate and standardize the associated finer particlesof the aggregate and cement in forming a surfacing face.

In my present invention I apply a trowelling action by imparting to themovable side member or members of the mold box a series of alternatingmajor movements interrupted by a larger series of alternating minormovements, thereby greatly increasing the efliciency of the trowellingfunction.

In other words, by imparting such a largely increased number of more orless minute back and forth intermediate minor movements to the facingelement, it greatly accelerates the surface collection and congestion ofthe finer particles, as well as the smoothing surface treatment, withgreatly improved results.

After prolonged experiments I have devised a machine which is capable offunctioning in the desired manner above stated, utilizing a wall plateacting on the block face preferably during pressing or tamping, 0raftertamping, or even when sufficiently plastic as to not require otherthan gravity settlement. 1

The invention is also successfully applicable to the modern so-calledvibrating or jolting machines.

In connection with the further description, reference will be had to theaccompanying for such treatment, in which:

present construction is in the gears II and I2.

Fig. 1 is a view in side elevation of a mold box provided with myimprovement;

Fig. 2 is a longitudinal vertical section thereof on the line II-II ofFig. 3;

Fig. 3 is a plan View of Fig. 1;

Fig. 4 is a transverse sectional view on the line IV-IV of Fig. 2;

Figs. 5 and 6 are detail diagrammatic views illustrating the operationof the driving mechanism for the smoothing wall plate;

Fig. '1 is a view similar to Fig. 4 showing a vertical application ofthe smoothing treatment;

Fig. 8 is a detail view showing a modified form of driving gear.

The block forming mold box, of double movable side form shown, isprovided with end Walls 2-2 rigidly mounted in any suitable manner asupon the supporting foundation 3. The side walls 4 are mounted betweenthe edges of such end walls and suitable guiding braces or framing 5,whereby they are maintained in closing engagement with the end walls,providing the usual rectangular cavity of proper dimensions for theintended block, as for instance, an 8x8x1 6" unit. The usual pallet 6 isutilized, either with or without a base plate I, resting upon thetransverse bottom 8 of any suitable construction, through which extendthe ejecting rams, aa for discharge of the finished unit.

For the purpose of imparting the desired movements to the side plates 4they are suitably connected with terminal journal bearings 9 at one endthrough which bearings extends the shaft 10 of a gear wheel H. Acompanion actuating gear I2 is mounted eccentrically on shaft I3 mountedin bearings M, which shaft is actuated in. any available manner, as by atrain of gears l5, [6, for imparting power from any suitable primemover, as motor M.

The particular feature of advantage in the As stated,.gear I2 in theconstruction shown, is mounted eccentrically so that as rotated itsperiphery will advance toward and recede from the normal pitch line of aconcentric actuating gear. Such gear ll being connected by shaft ID willmove the side plates 4 conformably, with return of the plates by actionof springs H or the like, as for instance, by counterweights.

However the springs as shown are of proper strength and are anchored atHi to stationary abutments of the framing and at the other end extendthrough flanges IQ of the outer ends of the, side plates, together withholding and adjusting nuts 20 for regulating the tension.

By such construction, or its equivalent, it will be seen that for eachrevolution of the driving gear or pinion l2 the side plates 4 will bethrust longitudinally, with return, to the same extent as willcorrespond to the eccentric throw of gear l2 in its action on gear ll,entirely irrespective of gear rotation.

However in order to provide for an increased series of minor orintermediate back and forth movements, occurring several times withinthe scope of the main back and forth movement alluded to, gear II isprovided at intervals, say in every third or fourth tooth space, with apartly filling abutment 2|.

In other words, the normal space between the teeth is partly filled sothat the entering tooth of pinion l2 will thus impart a sudden limitedbackward movement through gear ll, whether the eccentric gear I2 isadvancing or receding in its rotation. Alternatively, gear ll may be ofusual open tooth space type and driving gear 12 itself may have some ofits teeth elongated, as Zla, Fig. 8, for thrusting action against gearII.

It will be understood also that various impulses of the same generalkind may be had by combining a concentric pinion with a tooth spaceabutment gear, or an eccentric pinion with an ordinary gear, or as abovedescribed.

The net effect of such described movements is, as stated above, toinsure a continuous back and forth main movement to the sides 4 withlargely increased intermittent secondary back and forth movementscontinuously throughout the operation. The final effect of suchtreatment is to smooth, congest, and refine the texture of the blocksurface in the manner described.

Such effect is directly due to the alternating treatment imparted by thegear action and the reacting spring tension. I

Thus in Fig. 1 the driving pinion I2 is at its most receded position infull tooth engagement with gear H, and with the side plates 4 at theirfull receded position. As in Fig. 5, assuming the pinion I2 to be insubstantially the same position, its engaging tooth is shown as havingcome into contact with the intra-tooth abutment 2|, due to which suddenclearance interruption, the entire gear H and its shaft and the sides 4have been jarred backwardly a comparatively short distance, as at 22,with a corresponding short reversal by the following f ull depth toothengagement. Such action is repeated each time a successive abutmentcomes into mesh with a tooth of the pinion, and is continued throughoutthe revolution of both gears.

As shown in Fig. 6, pinion l2 has made a one half revolution, forcingthe side plates inwardly to the full extent of the entire eccentricvariation, as indicated at 23. It will therefore be clear that as longas the motor M is in operation the plates will be subjected to thecombined series of long and short movements as described.

It will be obvious that if desired, the driven gear may be regularwithout abutments between some of the teeth, and as a substitute for theabutments, some of the pinion teeth may be elongated, to produce thesame effect as in Fig. 8.

I show in Fig. 7 a modified construction in which the side plates 4a aremounted for vertical movement and in which similar gears H and I2 impartsimilar up and down interrupted trowelling movements, in the samecombination and relative frequency as in horizontal trowelling.

It will also be understood that gears I l and I2 may be transposed, i.e. the driving pinion may be truly concentric and driving an eccentricgear connected with the side plates.

Also, thatif desired the end plates may be actuated with stationary sideplates in horizontal oscillation, or both side and end plates may beactuated in vertical oscillation, such change merely involvingengineering design to suit conditions of use. With either form ofmachine it is also a fact that quite independent of the abutment/s 2| ineither gear, the mere combination of a driving and a driven gear ofcontinuously full open spaced teeth, one concentric and the othereccentric, will ensure a continuous series of the main full lengthoscillations of one or both wall plates, either side or end. Theintermeshing gears, instead of following annular pitch line engagement,are always in close abutting insertion of the teeth, and impart to theplates a constant series of bumping impulses, producing the desiredresult on the face of the block in a high degree.

With either such arrangement the general operation of charging theplastic aggregate into the mold; cavity is followed, with tamping as bytampers b, if used, smoothing off of the surplus, and final ejection ofthe block and removal on its pallet as is commonly practiced.

It will be understood that the motor may be operated continuously or maybe stopped and started for each successive unit manufactured, also thatthe block molding cavity may if desired be provided with a fixed wall atone side and a movable plate at the opposite side only.

Also that the construction of the machine may be changed and modified invarious details, dimensions or otherwise dependent on the product beingmade, but that all such changes are to be understood as within the scopeof the following claims.

What I claim is:

l. The method of making a concrete building block consisting insubjecting a molded body of plastic aggregate while in the mold andunder tamping pressure to a plate surfacing treatment of back and forthmajor trowelling movements including intermittent alternating similarminor movements.

2. A block making machine consisting of a mold having a supporting frameand side and end plates carried thereby, one of said plates consistingof a movable trowelling member, and means for reciprocating the wallplate back and forth through full length strokes with alternatingsimultaneous multiple shorter length strokes consisting of a drivinggear, a driven gear on the movable troweling member engaging the drivinggear, and a spring connected with the movable troweling member forholding the said gears in mesh.

3. In combination, a block forming mold having a frame and side and endwalls, one of the walls being slidably mounted on the frame for back andforth movement therein and provided with a shaft and a gear wheel havingcontacting abutments between some pairs of teeth, an intermeshingdriving gear therefor, and a retracting spring for the wall exertingtension thereon towards the driving gear.

4. In combination, a block forming mold having a frame and side and endwalls, one of the walls being slidably mounted on the frame for back andforth movement therein and provided with a shaft and a gear Wheel havingcontacting abutments between some pairs of teeth, an intermeshingeccentrically mounted driving gear therefor, and a retracting spring forthe movable wall eluding a frame and side and end Walls, one of theWalls being slidably mounted on the frame for alternating back and forthmovement therein and intermittent minor reverse forth and backmovements, said movable wall having connected with it a toothed gear, anactuating gear therefor, one of said gears being provided with a minornumber of abnormal depth teeth for effecting said reverse movements, anda retracting spring for the movable wall connected with the frame.

7. In combination, a block forming mold having a frame and, side and endwalls, one of said walls being slidably mounted on the frame for backand forth movement therein and provided with a gear wheel, anintermeshing driving gear therefor, and means exerting continuouspressure on the slidable wall and its gear wheel towards the drivinggear to effect abutting contact of the teeth of one of said gearsbetween the teeth of the other gear and against the bottom of itstooth-receiving space.

8. In combination, a block forming mold having a frame and side and endwalls, one of said walls being slidably mounted on the frame for backand forth movement therein and provided with a gear wheel, anintermeshing driving gear therefor, and a spring exerting continuouspressure on the slidable wall and its gear wheel towards the drivinggear to effect simultaneous intermeshing of the teeth of both gears andpositive abutting contact of the teeth of one of said gears against theinner bottom faces of the companion gear of such pair between the teeththereof.

FRANCIS J. STRAUB.

